Platelet-injector venturi carburetor for internal combustion engines

ABSTRACT

A venturi carburetor for an internal combustion engine which provides more effective fuel atomization, mixing and vaporization to improve performance and minimize undesirable combustion emissions. Gasoline or other liquid fuel is injected into five narrow rectangular venturi diffuser sections in the form of very finely atomized droplets from eight small injection orifices located within the throat of each of the five venturis. The fuel injection assembly includes five rectangular injector plates each of which comprises a bonded assembly of individual platelets having transfer orifices and complex hydraulic flow channels precisely formed therein by photoetching. Together the platelets form a series of fuel delivery passages connecting the fuel supply with the platelet injection orifices in the venturi throat. Idle and main fuel delivery circuits are integrated into the injector assembly and multiple throttle plates are provided so that only one injector and venturi is effective during idle operation.

United States Patent Kors et al. Oct. 21, 1975 [54] PLATELET-INJECTOR VENTURI 3,615,054 10/1971 Botz 239/555 C R O FOR INTERNAL 3,758,082 9/1973 Kertell 261/23 A COMBUSTION ENGINES FOREIGN PATENTS OR APPLICATIONS [75] Inventors; David L, Kors, El Dor do Hill 781,329 5/1935 France 261/41 C 1 Billy R. Lawver, Rancho Cordova;

John F. Addoms, Rocklin, all of Primary EXami'lerTim Miles Calif. Attorney, Agent, or Firm-John L. McGannon; Ronald S. L [73] Ass1gnee: Aero et-General Corporation, El aune Monte, Cahf. [57] ABSTRACT I Filedl y 1973 A venturi carburetor for an internal combustion en- [211 APPL No; 381,966 gine which provides more effective fuel atomization, m1x1ng and vapor1zat1on to improve performance and minimize undesirable combustion emissions. Gasoline Cl 261/23 261/41 or other liquid fuel is injected into five narrow rectan- 261/121 A; 239/555 gular venturi diffuser sections in the form of very [5 Cl. atomized droplets from eight small injection ori- Field of Search 26l/23 41 C, 41 A, fices located within the throat of each of the five ven- 261/121 A, 1316- 39; 239/555 turis. The fuel injection assembly includes five rectangular injector plates each of which comprises a References Cited bonded assembly of individual platelets having trans- UNITED STATES PATENTS fer orifices and complex hydraulic flow channels pre- 1,319,158 10/1919 Little 261/41 c cisely formed therein by photoetqhing- Together the 1,393,044 10/1921 Schulz..... 261/41 C platelets form a series of fuel del1very passages con- 1,449,664 3/1923 Friz 261/41 C necting the fuel supply with the platelet injection oril,758,954 5/1930 Linn 2 61/41 A fices in the venturi throat. Idle and main fuel delivery l,893,920 1/1933 Winfield 26l/DIG. 39 circuits are integrated into the injector assembly and g; a t?" multiple throttle plates are provided so that only one ar 3.181287 5/1965 Rabson 261/116 mjector and venturi effect've durmg Idle operatlon' 3,523,680 8/1970 Bartholomew 261/23 A 11 Claims, 5 Drawing Figures Q & l 50c 48 14 l 880 r 4 l T l 1 0 o a I I 4 -l I E l 4 a 460- l 46b l 46c\ l 46 o o t 40 4O 52 5 56 I I2 4 I so 5s 62 l US. Patent Oct.21,1975 Sheet2of2 3,914,347

PLATELET-INJECTOR VENTURI CARBURETOR FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The dual requirements of low allowable combustion exhaust emission levels established by government and high combustion efficiency required by industry im pose design criteria which .state-of-the-art internal combustion systems cannot meet. The plateletventuri carburetor of the present invention provides the capability for an internal combustion automotive engine to meet both emission and performance criteria.

Conventional venturi carburetors such as'used with automotive engines exhibit decreasing vaporization efficiency at higher air flow rates (e.g. above 40 SCFM). This is a direct result of the dual fuel delivery circuit design of such carburetors. At lower air flow rates only the idle circuit is operational producing a relatively fine gasoline droplet distribution. At higher flow rates however, the boost venturi becomes operational resulting in the formation of significantly larger gasoline droplets. Conventional carburetors produce maximum droplet sizes over an air flow range from 30-70 SCFM where flow is changing from the idle to main fuel delivery circuits. Good operation over this region is essential, however, since it represents a large percentage of total driving conditions.

The primary variables effecting fuel droplet size have been found to be the injector orifice diameter, local air velocity and fuel temperature. By minimizing the individual injector orifice size and using a large number of relatively small orifices, the present invention achieves fine scale fuel atomization. This approach to fuel injection in combination with the unique venturi design of the present invention also achieves more uniform mixing as well as more complete vaporization of the airfuel mixture.

Further, it has been established that diffusion droplet burning (with its inherent near stoichiometric temperature flame front) and local mixture ratio nonuniformities are major factors in the production of excessive NO, emissions. The fine atomization and uniform mixing provided by the platelet-venturi carburetor will thus significantly reduce NO, emission in internal combustion engines. Also, because of its superior vaporization characteristics, it will permit chokeless operation to minimize unburned hydrocarbons and carbon monoxide. Finally, the platelet-venturi carburetor is based on a design characterized by a minimum number of moving parts resulting in high production volume capability.

SUMMARY OF THE INVENTION The platelet-venturi carburetor is basically a carburetor which combines the venturi diffuser principle of fuel atomization, mixing and vaporization with platelet fuel injection technology recently developed in connection with gas-liquid mixing devices used for liquid fuel rocket engines.

The conventional venturi carburetor introduces fuel into a cylindrical venturi passage at its throat (i.e. point of minimum cross-sectional area) in the form of relatively large droplets. The fuel is either aspirated into the venturi by the difference in static pressure between the venturi and the fuel feed source (typically a float bowl) or is injected under pressure. Generally, aspiration of the fuel is preferred for automotive applications.

Air is drawn through the venturi by the pumping action of the pistons. The exact point of injection is determined by the required mixture ratio control over the throttle range. The large velocity difference between the air and fuel in the throat region causes atomization and dispersion of the fuel'droplets. Lateral pressure forces within the diffuser section of the venturi passage act to disperse the droplets such that a generally uniform mixture of vaporized fuel and air is produced at the diffuser exit.

In the platelet-venturi carburetor of the present invention, the venturi geometry has been optimized in the form of a plurality of narrow diffuser sections of rectangular cross-section to achieve greater uniformity of the air fuel mixture and a corresponding increase in vaporization efficiency. In addition, the fuel is introduced into the venturi throat via a number of very small orifices in the platelet injector assembly. The combination of many small injection orifices with the air shear effects produced within the venturi diffuser produces fine scale droplet atomization over the entire operating range of the carburetor. The resulting increase in the efficiency of atomization, mixing and vaporization leads to more complete combustion which is required for low exhaust emission levels.

The capability of the platelet-venturi carburetor to produce fine scale atomization and mixing is a direct result of a platelet injector design which is realizable through photoetch fabrication techniques allowing precise location of the extremely fine orifices and complex channel shapes. The precise location of each orifice and the large quantity of elements per unit area result in excellent mass and mixture ratio control within the intake manifold. The lack of restriction on distribution complexity due to the photoetch process permits flexibility of design to meet a wide variety of shapes and envelope requirements.

While the platelet-venturi carburetor is shown and described below in the context of an internal combustion automotive engine, it will be appreciated that the inventive concept can be easily applied to external combustion power plants, including jet engines, gas turbines, and even oil fired boilers.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewof a preferred embodiment of the platelet-venturi carburetor of the present invention;

FIG. 2 is an exploded perspective view of the carburetor of FIG. 1 illustrating the platelet-injector and venturi assemblies;

FIG. 3 is a perspective view of a generalized version of the rectangular venturi assembly used in the carburetor of the present invention;

FIG. 4 is a perspective view of the platelet-injector assembly of the carburetor including five individual injectors and associated fuel distribution manifold;

FIG. 5 is an exploded perspective view of the central platelet injector of the assembly of FIG. 4 which functions as the idle circuit injector.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings with specific reference to FIGS. 1 and 2, an exemplary embodiment of the platelet-venturi carburetor of the present invention is shown. The central elements of the carburetor both in terms of construction and operation are the venturi assembly l2 and the platelet injector assembly 14. These units are contained within a generally cubic carburetor housing formed by back plate 16, mounting plate 18, side plates and 22, base plate 24 and top plate 26. Base plate 24 bolts onto a conventional two-barrel automobile engine intake manifold and is provided with a central rectangular aperture 28 which connects the two rectangular barrels of the platelet-venturi carburetor with the ,corresponding circular induction ports of the intake manifold (not shown) through an adapter plate 30. Top plate 26 is likewise provided with a central rectangular aperture 32 which receives air intake through a conventional air filter device (not shown) mounted directly above the carburetor. FIG. 1 shows the carburetor with side plate 20 removed in order to more clearly show the internal arrangement of the individual platelet injectors and venturi vanes.

Attached to the exterior side of mounting plate 18 is a conventional fuel metering block 34 and float bowl 36. The float chamber and metering block may be of the type such as used in the Holley carburetor Model No. 46438, used by the Ford Motor Company. Float bowl 36 receives fuel through inlet fitting 38 from an external fuel tank via a fuel line (not shown). Gaskets 40 seal the assembled carburetor against fuel leakage.

In overall operation, air enters the carburetor through air intake 32 in top plate 26 and is mixed in the diffuser sections of venturi assembly 12 with finely atomized fuel droplets issuing from a total of 40 small orifices in the platelet injectors of assembly 14. Fuel passes from float chamber 36 through metering jets 42 in metering block 34. There are four jets, one pair for the two idle circuit fuel distribution channels and one pair for the two main circuit fuel distribution channels. The fuel flows up through passages in the metering block then out of the block into mounting plate 18. Passages in the mounting plate conduct the fuel into the distribution manifold of the platelet injector assembly l4.

Venturi assembly 12 defines two carburetor barrels each of which is composed of five narrow rectangular diffuser sections where the finely atomized fuel droplets are mixed with the incoming air and the mixture is vaporized. Each of the ten rectangular diffuser sections is formed by the confronting divergent surfaces of two adjacent venturi vanes 46a-46h together with the interior surface of either side plate 20 or 22 and central venturi divider plate 48. The four exterior venturi surfaces are formed by curved projections 50a-50d formed on the interior surfaces of back plate 16 and mounting plate 18.

The venturi vanes comprise airfoils having a profile which tapers gradually in the direction of air flow so that adjacent vane surfaces form a gas diffuser of gradually increasing rectangular cross-sectional flow area.

In general, the criteria for selecting the venturi geometry are that it must provide as high an air velocity as possible for good fuel atomization and vaporization and that the stagnation pressure loss within the diffuser be minimized. Referring now to the generalized venturi section of FIG. 3 the design parameters which have a bearing on the stagnation pressure loss are the diffuser angle'of divergence a, the throat width W, the throat length H, the diffuser length L, and the leading edge ra-.

dius r. Packaging constraints limit the venturi length L to about 2.00 in. Experimental testing has disclosed that the stagnation pressure loss increases with increasing air flow rate and decreases with venturi throat.

width. This dependence on throat width is due to boundry layer blockage since in the case of narrower throat width the boundry layer occupies a larger percentage of the total flow area.

Suitable values for the venturi design parameters with five diffuser sections per barrel have been experimentally determined as follows: venturi lengthLzZ in.,a half angle:3 /2, venturi throat width, W:0.l00 in. While a larger throat width would result in a smaller pressure drop as discussed above, it has been found that the spatial distribution of the fuel is not as good with a larger throat. The pressure drop requirement is met by using multiple venturis to provide the required open area for the maximum flow condition. A venturi section constructed as described resulted in a diffuser pressure loss of 1.5 in. hg. at the maximum flow of 350SCFM. It was estimated that diffuser inlet and exit losseswould not exceed 1.5 in. hg. so that the overall pressure drop should not exceed 3.0 in. hg. at 350 SCFM with five venturi sections having defined individual throat dimensions of 0.10 in. width by L50 in. length.

As has been-described the five venturi sections in each barrel of the carburetor are formed by four vanes 46 together with corresponding half-vane sections 50 formed in back plate 16 and mounting plate 18 and the planar interior surfaces of side walls 20 and 22 together with the planar surfaces of venturi central divider plate 48. It will be seen from an inspection of FIGS. 1 and 2 that the center two venturi vanes in each barrel (46b, 46c, 46f and 46g) have a greater length extending downwardly past the termination of the exterior vanes. The reason for this is that the lower portion of the central vanes in conjunction with the interior surfaces of carburetor walls 16, 18, 20 and 22, and the exterior surfaces of central divider plate 48 form three fuel induction passages 52, 54 and 56.

Rectangular throttle valve 58 is disposed within central passage 54 while the outer passages 52 and 56 are respectively provided with similar throttle valves 60 and 62. As best seen in FIG. 2 each of the three throttle valves is formed in two sections, one for each barrel, with a central rod portion which fits beneath divider plate 48. V

The purpose of this three duct configuration is to eliminate the need for the conventional dual fuel delivery circuit used in existing carburetors which produce undesirably large fuel droplets during acceleration; The idle circuit is formed by obstructing the outer passages 52 and 56 by closure of throttle valves 60 and 62 while central throttle valve 58 is maintained in an open position. In this condition only the center venturi section in each barrel is operable, thus providing one-fifth of the total fuel distribution area.

As will be discussed in detail below in connection with FIGS. 4 and 5, the fuel supply to the central platelet injector is isolated from the fuel supply to the main circuit injectors so that the fuel supply to the main injectors may be cut off during idle operation.

Platelet injector assembly 14 is shown in expanded detail in FIG. 4. The injector assembly comprises five injector units a-70e. Spacer blocks 72a-72f are interposed between the individual injector plates to maintain their relative spacing and also conduct fuel to the injectors. The dual circuit fuel distribution system is integrated into the injector assembly as follows.

Fuel distribution manifold 74 acts both as a mounting block by which the injector assembly is secured to mounting plate 18 and also distributes the incoming fuel to the idle and main fuel delivery circuits in the assembly. As discussed above in connection with FIGS. 1 and 2, fuel is conducted from float bowl 38 through metering block 34 which has four outlet orifices. These orifices align with ports 18a through l8d' in mounting block 18 (FIG. 2). The exterior ports 18a and 18d have an elongate shape so that the fuel issues therefrom on the interior side of mounting plate 18 at a slightly lower level on the plate with respect to the central two circular ports 18b and 180.

When injector manifold 74 is assembled to mounting plate 18 via two screws which engage threaded holes 84a and 84b the exterior elongate ports 18a and 18d in the mounting plate are enclosed within the periphery of V-shaped recess 76 in manifold 74. Thus, all fuel issuing from ports 18a and 18d will be collected within recess 76 and directed to the lower two fuel delivery passages 80a and 80b. Passages 80a and 80b are part of the main fuel distribution circuit and as will be seen serve as the fuel supply for the four outboard injector units 70a, 70b, 70d and 702. V

In a similar manner manifold recess 78 collects fuel issuing from interior ports 18b and 180 in mounting plate 18 and directs the fuel to the upper two fuel delivery passages 82a and 82b which are part of the idle circuit and supply fuel only to central injector 700.

Each of the individual injectors 70a and 70e and spacer blocks 72a-72fare provided with a centrally located four port pattern which is essentially identical to that formed in manifold 74 by passages 80a-b and 82a-b. The individual injector plate and spacers are secured together and attached to manifold 74 by means of an elongate bolt, the shank of which passes through aligned centrally located apertures 89 formed in the individual injectors and spacer blocks and the threads of which engage a threaded hole in the. manifold. Thus, when the injectors and spacers are assembled and secured to the manifold the aligned four-port pattern in the manifold, injectors and spacer blocks form the two upper channels 82a and 82b and the two lower channels 80a and 80b. The upper two channels supply fuel to the two injection circuits in'the central idle injector 70c while the lower two channels supply fuel to the two injection circuits in each of the four main injectors 70a, 70b, 70d and 70e.

Injector manifold 74 and each of the injector plates 70a through 702 are provided with aligned apertures 86a and 86b which receive alignment rods 88a and 88b. These rods extend through the manifold and the injectors and insure that the components of the assembly are maintained in a fixed relation to one another. A third alignment rod not visible in FIG. 4 is inserted through aligned apertures 86c in the manifold, injector plates and spacer blocks.

The internal construction of the centrally located idle circuit injector plate 700 is shown in FIG. 5. With the exception of the distribution platelets 90b and90fto be discussed below, injector 70c is identical to the main circuit injector plates 70a, 70b, 70d and 70e.

Injector 70c is composed of seven platelets 90a-90g which are bonded together to form a series of hydraulic flow passages and transfer orifices. This fuel distribution circuit connects the two idle circuit fuel delivery passages 82a-and 82b in upstream spacer block 720 and downstream spacer block 72d with eight small injection orifices 92in injection platelet 90d. As discussed above the central injector 700 is a part of the idle circuit only. Thus, the lower two fuel delivery passages 80a and 80b are not connected to injection orifices 92 and instead fuel in these passages passes'completely through the in jector via two aligned apertures in the central lower portion of each of platelets 90a through 90g. Conversely, in the case of the main circuit injectors a, 70b, 70d and 70s it is the lower two fuel delivery passages a and 80b which are connected to the injector platelet orifices and the upper two fuel delivery passages pass directly through the injectors.

The structure and function of the individual platelets I 900-903 will now be discussed. Cover platelets a and 90g form the outer fluid tight housing for injector 700. As discussed the cover platelets include the recurring four port fuel passage pattern as well as the central bolt receiving aperture 89 and the three alignment rod apertures 86a86c. When manifold vacuum increases fuel in the idle circuit delivery passage in either spacer block 720 or spacer block 72d is drawn by aspiration through the upper pair of apertures in cover platelets 90a and 90g respectively. Distribution platelets 90b and 90fare each provided with two sets of fuel distribu-' tion channels 94. These channels direct fuel passing through the upper ports of cover plates 90a and 90g to eight centrally aligned outlet ports 96 and thereafter through transfer ports 98 in transfer platelets 90c and 90f to eight injection channels 100 in injector platelet 90d. Each injector channel 100 also receives air via two air-bleed channels 102 entering the injection channel on either side. The fuel and air is mixed in mixer section 104 just upstream from injection orifice 92. 35

The addition of a small amount of air to each of the fuel injection channels 100 via two opposing air bleed channels 102 significantly improves the carburetor performance over conventional designs. It has long been recognized that a small amount of air premixed with fuel before injection into the main air stream reduces the effect of surface tension and causes fuel flow to approximate the compressible flow characteristics of the air at high flow conditions. The net result is to reduce the fuel flow sensitivity to temperature and air flow rate such that a more uniform air fuel ratio is obtained over the range of operating conditions. In conventional carburetor design the air bleed passages introduce air into apre-mixing section considerably upstream of the venturi throat. This results in a lack of fuel control due to the possibility of separation of the air-fuel mixture within the distribution channels.

In the present invention the air is introduced into each fuel orifice within the platelet very near the point of injection of the fuel into the venturi. This is far superior in providing uniform air-fuel mixture in that both fuel and air flows are controlled right up to the injection point. A further advantage of introducing the air bleed very near the fuel injection point is that it prevents fuel flow pulsations which are inherent in conventional carburetors. An incidental benefit is some initial atomization and vaporization of the fuel.

It has been experimentally determined that the particular configuration of the air-bleed passages shown in FIG. 5 wherein the air enters the fuel channel from both sides results in an oscillatory flow condition wherein the fuel stream moves back and forth across the channel at very high frequencies on the order of 3000 to 4000 cycles per second. These oscillations allow the fuel to flow freely at low suction pressures and also produce a significant amount of initial atomization at the higher air flow rates. It has also been found desirable to bevel the downstream edges of the platelet injectors to reduce the blockage area in the venturi throat and minimize the pressure drop within the diffuser. Fuel is aspirated out of the platelet injection orifices by the reduced pressure in the venturi throat created by the high velocity air passing through the venturi.

An additional reduction in emission levels can be achieved by further maximizing the fuel vaporization process within the carburetor by heating the air fuel mixture. This can be accomplished, for example, by electrical heating means within the platelets or by recycling a percentage of the combustion product through the carburetor to provide the necessary heat of vaporization. Thus, the heat transfer mechanism can be either by conduction through the heated platelets or by direct mixing of the exhaust gases with the fuel. The latter approach is preferred since exhaust gas recirculation (ERG) is a currently popular technique for reducing NO emissions.

The construction of the individual platelets for the main injectors 70a, 70b, 70d and 70e is essentially identical to that of idle injector 700 with the sole exception that the distribution platelets thereof corresponding to platelet 90b have the fuel distribution channels 94 inverted top to bottom to communicate with the main fuel circuit flow within lower delivery channels 80a and 80b.

The photoetch fabrication process by which the complex channel shapes the precisely located orifices are formed is particularly well adapted to low cost mass production techniques. Once the basic artwork and negatives have been made the manufacture of the platelets is a repetitive process requiring little supervision. Quality control requirements are almost nonexistent since each platelet is a faithful reproduction of the photographic negative. The assembly of the sequence numbered platelets is almost foolproof and can be rapidly accomplished by low cost labor. The final assembled product is readily inspected by visual methods for acceptability.

While a preferred embodiment of the invention has been shown and described above it will be appreciated by those skilled in the art that the basic principles of the invention can be implemented using a variety of specific structural forms. For example, rather than being arranged in parallel with the venturi sections the individual injector plates may be disposed at right angles thereto. Other similar variations or modifications of the invention will become apparent to the reader and the preceding embodiment is to be considered exemplary only.

What is claimed is:

1. A carburetor for an internal combustion engine comprising a venturi assembly defining a plurality of air diffuser channels of narrow rectangular cross-sectional flow area and a fuel injector assembly including a plurality of generally rectangular injector plates each having a plurality of small fuel injection orifices at the lower portion thereof, each of said injector plates comprising a plurality of platelet elements together defining fuel flow passages interconnecting a fuel source with said injector orifices, said injector plates being so posilioned with respect to said diffuser channels that said orifices are located therein at the throat portion thereof to introduce fuel thereat in the form of finely atomized droplets.

2. The carburetor of claim 1 wherein said fuel flow passages include a plurality of injector channels connected to said injection orifices, a mixing area between said injector channels and said orifices and a plurality of air bleed passages communicating with said mixer section.

3. In a venturi carburetor of the type having a plurality of diffuser sections for mixing and vaporizing an air fuel mixture, the improvement comprising:

a plurality of vanes of generally rectangular shape and tapered profile, adjacent surfaces of said vanes defining a diffuser section of narrow rectangular cross-sectional air flow area, and

fuel injection means for introducing fuel into said venturi sections in the form of finely atomized droplets, said injection means including a plurality of injector plates each having a plurality of small injection orifices centrally disposed within a corresponding one of said venturi sections at the throat thereof.

4. The carburetor of claim 3 wherein certain ones of said vanes extend downwardly below the termination of adjacent vanes forming a plurality of fuel induction channels.

5. Apparatus of claim 4 wherein each of said induction channels is provided with throttle means for selective operation thereof.

6. The combination of a platelet fuel injector assembly and a multiple venturi carburetor wherein said venturis have an elongate cross-sectional flow area and including a plurality of injector plates of laminar construction each including a plurality of platelets having small hydraulic flow passages formed therein terminat ing at a plurality of injection orifices, said injector assembly being so disposed within said venturis to locate a plurality of said orifices within each of said venturis along the major axis thereof and fuel delivery means connecting said injection orifices with a fuel source.

7. The injector assembly of claim 6 wherein said fuel delivery means includes dual fuel distribution channels, one of said channels communicating with one of said injector plates and the other of said channels communicating with the remainder of said injector plates.

8. A carburetor for an internal combustion engine comprising:

venturi means defining at least one air flow passage of elongate cross-sectional flow area and having a throat section and a diffuser section and platelet fuel injector means associated with said venturi passage and including a plurality of small fuel injection orifices disposed within said venturi throat section, said platelet fuel injector means further comprising at least one injector plate disposed within said venturi passage so that said injection orifices are disposed along the major axis thereof, said injector plate being of laminar construction wherein a plurality of platelet elements having fuel flow channels and transfer orifices formed therein are bonded together to define fuel flow passages connecting an external fuel source with said injection orifices.

9. The carburetor of claim 8 further comprising a plurality of rectangular throttle plates disposed within 9 10 said venturi passages to selectively control the air flow 11. A carburetor for an internal combustion engine therethrough. comprising:

10. A carburetor for an internal combustion engine venturi means defining at least one air flow passage comprising: having a throat section and a diffuser section and venturi means defining at least one air flow passage having a throat section and a diffuser section and platelet fuel injector means associated with said venplatelet fuel injector means associated with said venturi passage and including a plurality of small fuel injection orifices disposed within said venturi turi passage and including a plurality of small fuel injection orifices disposed within said venturi throat section, said platelet fuel injector means furnar construction wherein a plurality of platelet elether comprising at least one injector plate of lamiments having fuel flow channels and transfer orinar construction wherein a plurality of platelet elefices formed therein are bonded together to define ments having fuel flow channels and transfer orifuel flow passages connecting an external fuel fices formed therein are bonded together to define source with said injection orifices, said fuel injector fuel flow passages connecting an external fuel means further having fuel distribution means assosource with said injection orifices, said injector ciated with said injector plates and comprising two plates further having a plurality of air bleed pasisolated fuel delivery circuits, one of said circuits sages formed therein and wherein each of said fuel communicating only with a selected one of said flow passages has at least one of said air bleed pasplates and the other of said circuits communicating sages connected thereto in proximity of said oriwith the others of said plates. fices.

throat section, said platelet fuel injector means further comprising at least one injector plate of lami- 

1. A CARBURATOR FOR AN INTENAL COMBUSTION ENGINE COMRISING A VENTURI ASSEMBLY DEFINING A PLURALITY OF AIR DIFFUSER CHANNELS OF NARROW RECTANGULAR CROSS-SECTIONAL FLOW AREA AND A FUEL INJECTOR ASSEMBLY INCLUDING A PLURALITY OF GENERALLY RECTANGULAR INJECTOR PLATES EACH HAVING A PLURALIYT OF SMALL FUEL INJECTION ORIFICES AT THE LOWER POTION THEEOF, EACH OF SAID INJECTOR PLATES COMPRISING A PLURALITY OF PLATELET ELEMENTS TOGETHER DEFINING FUEL FLOW PASSAGES INTERCONNECTING A FUEL SOURCE WITH SAID INJECTOR ORIFICES, SAID INJECTOR PLATES BEING SO POSITIONED WITH RESPECT TO SAID DIFFER CHANNELS THAT SAID ORIFICES ARE LOCATED THEREIN AT THE THROAT PORTION THEREOF TO INTRODUCE FUEL THEREAT IN THE FORM OF FINELY ATOMIZED DROPLETS
 2. The carburetor of claim 1 wherein said fuel flow passages include a plurality of injector channels connected to said injection orifices, a mixing area between said injector channels and said orifices and a plurality of air bleed passages communicating with said mixer section.
 3. In a venturi carburetor of the type having a plurality of diffuser sections for mixing and vaporizing an air fuel mixture, the improvement comprising: a plurality of vanes of generally rectangular shape and tapered profile, adjacent surfaces of said vanes defining a diffuser section of narrow rectangular cross-sectional air flow area, and fuel injection means for introducing fuel into said venturi sections in the form of finely atomized droplets, said injeCtion means including a plurality of injector plates each having a plurality of small injection orifices centrally disposed within a corresponding one of said venturi sections at the throat thereof.
 4. The carburetor of claim 3 wherein certain ones of said vanes extend downwardly below the termination of adjacent vanes forming a plurality of fuel induction channels.
 5. Apparatus of claim 4 wherein each of said induction channels is provided with throttle means for selective operation thereof.
 6. The combination of a platelet fuel injector assembly and a multiple venturi carburetor wherein said venturis have an elongate cross-sectional flow area and including a plurality of injector plates of laminar construction each including a plurality of platelets having small hydraulic flow passages formed therein terminating at a plurality of injection orifices, said injector assembly being so disposed within said venturis to locate a plurality of said orifices within each of said venturis along the major axis thereof and fuel delivery means connecting said injection orifices with a fuel source.
 7. The injector assembly of claim 6 wherein said fuel delivery means includes dual fuel distribution channels, one of said channels communicating with one of said injector plates and the other of said channels communicating with the remainder of said injector plates.
 8. A carburetor for an internal combustion engine comprising: venturi means defining at least one air flow passage of elongate cross-sectional flow area and having a throat section and a diffuser section and platelet fuel injector means associated with said venturi passage and including a plurality of small fuel injection orifices disposed within said venturi throat section, said platelet fuel injector means further comprising at least one injector plate disposed within said venturi passage so that said injection orifices are disposed along the major axis thereof, said injector plate being of laminar construction wherein a plurality of platelet elements having fuel flow channels and transfer orifices formed therein are bonded together to define fuel flow passages connecting an external fuel source with said injection orifices.
 9. The carburetor of claim 8 further comprising a plurality of rectangular throttle plates disposed within said venturi passages to selectively control the air flow therethrough.
 10. A carburetor for an internal combustion engine comprising: venturi means defining at least one air flow passage having a throat section and a diffuser section and platelet fuel injector means associated with said venturi passage and including a plurality of small fuel injection orifices disposed within said venturi throat section, said platelet fuel injector means further comprising at least one injector plate of laminar construction wherein a plurality of platelet elements having fuel flow channels and transfer orifices formed therein are bonded together to define fuel flow passages connecting an external fuel source with said injection orifices, said injector plates further having a plurality of air bleed passages formed therein and wherein each of said fuel flow passages has at least one of said air bleed passages connected thereto in proximity of said orifices.
 11. A carburetor for an internal combustion engine comprising: venturi means defining at least one air flow passage having a throat section and a diffuser section and platelet fuel injector means associated with said venturi passage and including a plurality of small fuel injection orifices disposed within said venturi throat section, said platelet fuel injector means further comprising at least one injector plate of laminar construction wherein a plurality of platelet elements having fuel flow channels and transfer orifices formed therein are bonded together to define fuel flow passages connecting an external fuel source with said injection orifices, said fuel injector means further having fuel distribution means associated with said injector plates and comprising two isolated fuel delivery circuits, one of said circuits communicating only with a selected one of said plates and the other of said circuits communicating with the others of said plates. 